Anti-rebound device for sewing machines



March 31, 1964 J. P. ARTER ANTI-REBOUNDDEVICE FOR SEWING MACHINES 3 Sheets-Sheet 1 Filed Feb. 12, 1962 Invenlor 172177186 2? Carter 3y kzb'Aiforney March 31, 1964 J. P. CARTER ANTI-REBOUND DEVICE FOR SEWING MACHINES 3 Sheets-Sheet 2 Filed Feb. 12, 1962 March 31, 1964 J. P. CARTER 3,126,851

ANTI-REBOUND DEVICE FOR SEWING MACHINES Filed Feb. 12, 1962 3 $h88tS-Sh88t 3 2 50 6% 53 F .5 (g 62 52 P 34 United States Patent Office 3,126,851 Patented Mar. 31, 1964 James P. Carter, Beverly, Mass, assignor to United Shoe Machinery Corporation, Boston, Mass., a corporation of New Jersey Filed Feb. 12, 1962, Ser. No. 172,550 6 Claims. (Cl. 112-213) This invention relates to stopping mechanisms for machines having shafts or other rotating parts which, at the end of an operating period of discretionary or variable duration, must be brought to rest in precise angular positions. More particularly the invention is directed to such mechanisms which include positioning clutches which, during a stopping cycle, drive the rotary parts to the stopping position in a direction which is the reverse of the normal operating direction of their parts and further in which the reverse drive, during the stopping cycle, is utilized for accomplislung an auxiliary function necessary in bringing the machine to rest but not needed during continuing operaion of the machine.

An example of such a machine is that disclosed in United States Letters Patent No. 2,359,662, issued upon application of Alfred R. Morrill. In the Morrill machine starting is under the control of an operator who depresses a treadle to cause engagement of a main clutch for driving a cam shaft in a forward direction during continuing operation of the machine. Stopping of the machine with the cam shaft in a predetermined angular position is accomplished by disengaging the main clutch and engaging an auxiliary reverse driving clutch which first brings the cam shaft to a stop at a random position and then drives it in the reverse direction to the predetermined position. A pair of stop members, one of which rotates with the shaft, and the other of which is pivoted on the machine frame, engage to determine the stopping position.

Increasing the reverse driving speed in the Morrill machine very desirably reduces the duration of the stopping cycle and accordingly improves the overall efficiency of the machine. However, increased impact upon engagement of the stopping members causes the shaft to rebound in the forward direction, the degree of rebound being proportional to the reverse speed. Since the Morrill machine includes a thread finger which is actuated during reverse motion of the cam shaft to grip the thread to prepare for the start of the next operation an appreciable rebound of the shaft causes the thread finger to release the thread as would normally happen only upon restarting of the machine for the next sewing operation.

It is accordingly a general object of the present invention to provide a simple mechanism for arresting rotary parts of a machine accurately in a predetermined position.

Another object is to shorten the duration of the stopping cycles of machines in which rotary parts must be arrested in predetermined positions by permitting higher driving speeds during stopping cycles.

The foregoing objects are achieved in a sewing machine of the Morrill type or any other machines having comparable requirements of accuracy in stopping by a device including a latch coupled to the control means of the machine which may be in the form of a treadle rod. The connection between the latch and treadle rod in the Morrill machine is such that before rotation is imparted to parts of the machine the latch is disengaged and is thereafter maintained in disabled position during continued operation of the machine. The latch is formed and located to engage a surface on the related shaft to prevent rebounding of the shaft away from the stopping position. Upon movement of the control rod from operating position to machine stopping position the connection between the latch and the treadle rod frees the latch to engage the surface on the shaft after the direction of rotation of the shaft has been reversed. In order to eliminate the possibility of latch engagement immediately after the treadle rod is shifted to stopping position and before the momentum of the shaft has been reduced, buffer means is associated with the latch according to a feature of the invention. The buffer means is in the form of a pivoted finger resiliently urged into a latch shielding position. Carried on the shaft is a dog which engages the finger to cam it out of its shielding position after the direction of rotation of the shaft has been reversed so that the latch may engage the surface on the shaft as the predetermined position of the shaft is reached and thereby prevent return motion resulting from impact of engagement of the stop members.

The foregoing objects and features of the invention will be appreciated and a more complete understanding gained from the following detailed description of an illustrative embodiment taken in connection with the accompanying drawings in which:

FIG. 1 is a View in right side elevation of the Morrill machine in which an anti-rebound device according to the present invention, has been installed;

FIG. 2 is a fragmentary view in right side elevation of the anti-rebound device of the invention shown with the associated sewing shaft in stopped position;

FIG. 3 is a detailed plan view of the anti-rebound device of FIG. 2;

FIG. 4 is a view similar to FIG. 2 but showing the parts of the device in the positions which they occupy while the machine is in operation;

FIG. 5 is a detail schematic view in right side elevation showing a shaft and stop members of the Morrill machine in the process of being stopped;

FIG. 6 is a detail view of some of the parts of FIG. 5 shown in stopped condition of the machine; and

FIG. 7 is a fragmentary view in right side elevation showing instrumentalities affected in stopping the machine.

As seen in FIGS. 1 and 5 to 7 inclusive, the machine according to the Morrill patent includes a frame 10 in which is rotatably supported a horizontal cam shaft 12 corresponding to that hearing the reference numeral 132 in the patent. Among the instrumentalities actuated by cams on the shaft 12 are a curved hook needle 14, a looper 16 and a channel guide 18 which cooperate in the formation of stitches for attaching a welt 2% to a lasted shoe upper indicated generally at 22.

For starting the Morrill machine there is provided an operator-actuated treadle 24 pivoted on the frame iii and connected to a vertical treadle rod 26. At the upper end of the treadle rod 26 is a pair of check nuts 28 bearing against the upper end of a compression spring 30 which is coiled around the rod and engages a forked lever arm 31 fixedly supported on a rockshaft 32 corresponding to the rockshaft 172 of the patent. For driving the shaft 12 in a forward or clockwise direction, as seen in FIGS. 5 and 6, to operate the machine, a forked clutch control lever 33 on the rockshaft 32, which is biased in a counterclockwise direction as seen in FIG. 5 by a spring 34, causes the engagement of a main driving clutch more fully described in the patent. The treadle rod 26 is maintained in depressed position by a latch bar 35 entering a notch 36 in the rod. After the treadle 24 has been depressed and the shaft 12 has begun to rotate the Morrill machine continues in operation until the rod 26 is released automatically by the bar 35 to initiate a machine stopping cycle. The release of the treadle rod 26 allows the rockshaft 32 under the force of the spring 34 to turn in a reverse or counterclockwise direction as seen in FIG. 5 and thereby to raise a lock bolt 38 corresponding to that bearing the reference numeral 164 in the patent. The

'32 are the same as those of the patent and include an arm 39 fixed to the rockshaft 32 to which arm the spring 34 anchored to the frame, is connected. When the bolt 38 is raised, it causes the engagement of a reverse driving clutch Which first arrests rotation of the shaft in the clockwise direction and then drives the shaft in a counterclockwise direction to a predetermined stop position as more fully described in the patent.

lmost directly above the shaft 12 is a pivot shaft 49 upon which is loosely supported a stop arm 42 corresponding to the stop arm 167 of the patent. At its distal end the stop arm 42 carries a follower roll 44 and it is also pivotally connected to a link 4-6. As is more fully explained in the patent, the follower roll 44 cooperates with a cam disk 48 in stopping the machine but the stop arm 42 is so arranged that during operation of the machine the follower roll is held out of contact with the disk. When the treadle rod 26 is raised, however, the arm 42 is pivoted on the shaft 40 to bring the roll 44 into engagement with the cam 48 so that the roll may enter a groove 50 for bringing the machine to rest in a predetermined position when the roll 44 reaches the end of the groove. As the shaft 12 continues during the stopping cycle to revolve in a counterclockwise direction the roll 44- is moved inwardly toward the shaft 12 by the configuration of the groove d causing the link 46 to move downwardly and an integral collar 52 to engage the slotted ear of a cam lever 54 which is thereby rocked in a clockwise direction as seen in FIG. 5. The cam lever 54 carries a follower roll 56 and is pivotally connected to a link 58 for operating a thread finger 6h seen in FIG. 7. During normal operation of the machine the follower roll 56 is acted upon by a complete cam groove 62 to actuate the thread finger through the link 5% to perform its regular thread manipulating function for the formation of each stitch. In stopping the machine, however, the engagement of the collar 52 with the cam lever 54 causes the roll 56 to enter an extension 64 thereby forcing the link 58 and the thread finger to an extreme rearward position in which the finger grips the thread indicated at 66 before the follower roll 44 arrests rotation of the shaft 12 by contacting the end of the groove St).

The rearward motion of the thread finger on into thread gripping position is completed during the last few degrees of rotation of the shaft in the reverse direction. Accordingly when the follower roll 44 engages the bottom of the groove 50 with impact there is an unavoidable rebound of the shaft 12 in the clockwise direction, as seen in FIG. 5, with the result that the thread 66 is frequent ly released by the thread finger 60. In order to avoid this unpredictable and otherwise uncontrollable rebound motion, an anti-rebound device according to the invention has been installed at the right end of the shaft 12.

The anti-rebound device as shown in FIGS. 1 to 4 comprises an arm 70 pivoted on a screw 72 passing through a box-like housing 74 on the outside of the frame lit and into threaded engagement with a tapped hole in the frame. The housing 74 is additionally secured to the frame it) by another bolt 76.

The arm 74 includes a latch 78 which cooperates with a disk 80 fixedly secured to the end of the shaft 12 and notched to present a generally radial latch engaging surface 82. So as to provide an adjustment of the effective position of the latch '78, the arm 7% is formed with a hub 84 in which is received an eccentric bushing 85 having an enlarged perforated head 38. The hub 84 is free to pivot between the head 88 and the frame it} and the effective position of the latch is varied by turning the bushing 86, 83 as required and then locking it in place by means of the screw 72.

While the treadle rod 26 is depressed and the machine is in operation the latch 78 is maintained in inactive posi tion spaced from the disk 8% as shown in FIG. 4, by connections with the rockshaft 32. For this purpose an arm 9th is fixed to the rockshaft 32 and at its free end has pivoted to it a rod 92. passing freely through an opening in the distal end of the arm 76. A spring 94 is wrapped about the rod 92: and compressed by a collar 96 toward the arm 7i) and a second collar 98 is adjustably fixed on the rod to limit the movement of the arm under the bias of the spring.

To prevent damage resulting from engagement of the latch 78 with the surface 82 immediately as the rod 26 rises to its machine stopping position and before the reverse elutch has slowed down the forward rotation of the shaft 12', a finger 1% is pivoted on the arm 7%. The finger llfitl is biased against a stop pin 1'62 by a tension spring liti stretched between the finger and a lug on the arm 7%. While the finger 1% rests against the pin W2 it rides on the disk 84) and thus shields the latch 78 against engagement with the surface 82. When the treadle rod 25 rises the pressure of the spring 3t) is relieved and the rockshaft 32 is pivoted in a counterclockwise direction as seen in FIGS. 2 and 4 by the action of a main clutch spring and of the spring 3d. The effect of the counterclockwise rocking of the shaft 32 is to compress the spring $4 as the collar 93 moves away from the arm 79. At this time the latch 78 is still prevented from engaging the surface 82 by the shielding effect of the finger 1% bearing upon the full diameter of the disk $13. On the periphery of the disk 8% is a dog having a generally radial surface 1% which engages the finger tilt] and causes it to move away from the stop pin 1%, and once the finger has passed beyond a generally radial line extending from the axis of the shaft 12 through the pivot of the finger the spring 94 pressing downwardly on the arm 7% is effective to complete the withdrawal of the finger from its latch shielding position. The dog including the radial surface 106 is formed with a gently sloping or escapment back :which causes no more than a gentle lifting of the arm 70 away from the shaft 12 in the event of continued motion of the shaft in a clockwise direction, as seen in FIGS. 2 and 4 after the treadle rod has risen. Such continued clockwise motion of the shaft 12 could occur if for some reason the main clutch failed to disengage or the reverse clutch were partially or totally ineffective in arresting shaft rotation.

The iatch 73 is positioned immediately beyond the surface 8-2 as the roll 44 engages the bottom of the groove 5h. The adjustment of the effective position of the latch 73 is made with a high degree of accuracy by adjusting the angular position of the eccentric bushing 86, 8%.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a machine having a frame, a shaft rotated continuously in a forward direction during normal operation of the machine and brought to rest in a predetermined angular position during a stopping cycle by rotation in the reverse direction, control means shiftable between an operating position for causing forward rotation of the shaft and a stopping position for initiating the stopping cycle, a rotary stop member mounted on the shaft and a movable member on the frame and engageable by the rotary member for arresting rotation of the shaft in the predetermined angular position, an anti-rebound device comprising a latch on the frame, a latch engaging surface on the shaft, connecting means between the latch and the control means for disabling the latch While the control means is in operating position, and buffer means responsive to rotation of the shaft in the reverse direction after shifting of the control means to stopping position for permitting engagement of the latch with the surface only after the direction of rotation of the shaft has been reversed.

2. In a machine having a frame, a shaft rotated continuously in a forward direction during normal operation of the machine and brought to rest in a predetermined angular position during a stopping cycle by rotation in the reverse direction, control means shiftable between an operating position for causing forward rotation of the shaft and a stopping position for initiating the stopping cycle, a rotary stop member mounted on the shaft and a movable member on the frame and engageable by the rotary member for arresting rotation of the shaft in the predetermined angular position, an anti-rebound device comprising a latch pivoted on the frame and spring biased toward the shaft, a latch engaging surface on the shaft, connecting means between the latch and the control means for holding the latch away from the shaft against the spring bias while the control means is in operating position, and buffer means for preventing engagement of the latch with the surface until after the direction of rotation of the shaft has been reversed.

3. In a machine having a frame, a shaft rotated continuously in a forward direction during normal operation of the machine and brought to rest in a predetermined angular position during a stopping cycle by rota-tion in the reverse direction, control means shiftable between an operating position for causing forward rotation of the shaft and a stopping position for initiating the stopping cycle, a rotary stop member mounted on the shaft and a movable member on the frame and engageable by the rotary member for arresting rotation of the shaft in the predetermined angular position, an anti-rebound device comprising an arm pivoted on the frame, a latch formed integral with the arm, a latch engaging surface on the shaft, means including an eccentric bushing in the arm for adjusting an engaging position of the latch, connecting means between the arm and the control means for disabling the latch while the control means is in operating position, and buffer means including a finger pivoted on the arm and extending in shielding relation with the latch for preventing engagement of the latch with the surface until after the direction of rotation of the shaft has been reversed.

4. In a machine having a frame, a shaft rotated continuously in a forward direction during normal operation of the machine and brought to rest in a predetermined angular position during a stopping cycle by rotation in the reverse direction, control means shi-ftable between an operating position for causing forward rotation of the shaft and a stopping position for initiating the stopping cycle, a rotary stop member mounted on the shaft and a movable stop member on the frame and engageable by the rotary member for arresting rotation of the shaft in the predetermined angular position, an anti-rebund device comprising an arm pivoted on the frame, a latch on the arm, a disk on the shaft formed with a latch engaging surface, connecting means between the arm and the control means for disabling the latch while the control means is in operating position, a finger pivoted on the arm, resilient means for urging the finger into latch shielding position in which the finger engages the periphery of the disk after movement of the control means to stopping position and the latch is prevented from engaging the surface, and means carried on the disk for camming the finger out of its latch shielding position after the direction of shaft rotation has been reversed but before engagement of the stop members.

5. In a machine having a frame, a shaft rotated continuously in a forward direction during normal operation of the machine and brought to rest in a predetermined angular position during a stopping cycle by rotation in the reverse direction, control means shiftable between an operating position for causing forward rotation of the shaft and a stopping posit-ion for initiating the stopping cycle, a rotary stop member mounted on the shaft and a movable member on the frame and engageable by the rotary member for arresting rotation of the shaft in the predetermined angular position, an anti-rebound device comprising an arm on the frame, a latch on the arm, a latch engaging surface on the shaft, connecting means between the latch and the control means for disabling the latch while the control means is in operating position, and means effective for preventing engagement of the latch with the surface until after the direction of rotation of the shaft has been reversed including a latch shielding finger pivoted on the arm and a dog on the shaft having an escapement surface engageable by the finger during forward rotation of the shaft and a finger camming surface effective during reverse rotation of the shaft.

6. In a sewing machine having a frame, a treadle rod movable betwen operating and stopping positions, a. sewing shaft rotated in a forward direction during sewing operations and brought to rest in a predetermined angular position during a stopping cycle by rotation during a stopping cycle in a reverse direction, a rotary stop member mounted on the shaft and a movable member on the frame engageable by the rotary member for arresting rotation of the shaft in the predetermined angular position, an anti-rebound device for preventing return rotary motion of the shaft from its predetermined position comprising a disk fixedly supported on the shaft and presenting a latch engaging surface, an arm pivoted on the frame, resilient means urging the arm toward the disk when the treadle rod is in stopping position, a latch on the arm, connecting means between the arm and the treadle rod for holding the latch out of contact with the disk while the rod is in operating position, and buffer means for preventing engagement of the surface by the latch until after the direction of rotation of the shaft has been reversed.

References Cited in the file of this patent UNITED STATES PATENTS 2,195,890 McCann Apr. 2, 1940 2,359,662. Morrill Oct. 3, 1944 2,385,768 Althens Oct. 2, 1945 2,563,854 Maxant Aug. 14, 1951 

1. IN A MACHINE HAVING A FRAME, A SHAFT ROTATED CONTINUOUSLY IN A FORWARD DIRECTION DURING NORMAL OPERATION OF THE MACHINE AND BROUGHT TO REST IN A PREDETERMINED ANGULAR POSITION DURING A STOPPING CYCLE BY ROTATION IN THE REVERSE DIRECTION, CONTROL MEANS SHIFTABLE BETWEEN AN OPERATING POSITION FOR CAUSING FORWARD ROTATION OF THE SHAFT AND A STOPPING POSITION FOR INITIATING THE STOPPING CYCLE, A ROTARY STOP MEMBER MOUNTED ON THE SHAFT AND A MOVEABLE MEMBER ON THE FRAME AND ENGAGEABLE BY THE ROTARY MEMBER FOR ARRESTING ROTATION OF THE SHAFT IN THE PREDETERMINED ANGULAR POSITION, AN ANTI-REBOUND DEVICE COMPRISING A LATCH ON THE FRAME, A LATCH ENGAGING SURFACE ON THE SHAFT, CONNECTING MEANS BETWEEN THE LATCH AND THE CONTROL MEANS FOR DISABLING THE LATCH WHILE THE CONTROL MEANS IS IN OPERATING POSITION, AND BUFFER MEANS RESPONSIVE TO ROTATION OF THE SHAFT IN THE REVERSE DIRECTION AFTER SHIFTING OF THE CONTROL MEANS TO STOPPING POSITION FOR PERMITTING ENGAGEMENT OF THE LATCH WITH THE SURFACE ONLY AFTER THE DIRECTION OF ROTATION OF THE SHAFT HAS BEEN REVERSED. 